Hello TomoYou, and a warm welcome to the forums.
What you have told us has been a big talking point on these forums because 'intrusive thoughts' are part of OCD and I can say this simply because I have it, so if you type 'intrusive thoughts' into the search bar above there will be much there for to look at.
This isn't your fault but part of this illness and I definitely understand how you are feeling.
Please get back and ask any questions you like, but can I suggest you get a referral to see a psychologist by asking your doctor for a 'mental health plan', this entitles you to 10 Medicare paid sessions.
Hope to hear back from you.